In this series on Looking Back & Looking Forward, we are reviewing a green home we built over 2 years ago, the lessons learned and more importantly, how we can (or even how you can) utilize those lessons on future builds. As a quick recap, we have looked at some of the unique issues we were facing, designing & modeling an energy efficient structure, and finally the layout & orientation of the building. While we gave you a sneak preview in the last article of the footing & foundation system we used, let us take a few minutes to review some basics.
In the simplest terms, a footing is what your foundation walls are placed on. The footing is typically twice the width of the foundation wall. The actual determination for the proper size of the footing must be made by an engineer, who knows what your soil conditions are, the weight it will have to support and numerous other factors.
There are three main types of foundations commonly used in most areas of the country; Slab on Grade, Crawlspace, & Basement. While these are the three main common systems, there are numerous options available. A little research, spending a few more bucks, spending a few extra minutes to make sure everything is square and level will save you in the future big time.
Slab on Grade:
The slab on grade foundation is generally a monolithically poured foundation system consisting of a structural concrete slab with integrated footings poured directly on the grade. There are no accessible spaces under the slab so all your drain lines & / or water lines need to be located in the proper places before you pour it. While some individuals do not think it is necessary to install insulation under the slab, I strongly suggest you consider it based on the relatively low cost compared to all the benefits.
A crawlspace is basically made up of a footer, followed up by a masonry foundation wall that has ventilation and an accessible space that varies from 30” up to 8’. While this used to be considered a great system, for today’s houses (or retrofitting an older house), an insulated enclosed crawl space is the newest gold standard for quite a few good reasons that we will delve into in a future article. A few quick tips on this system are to use Insulated Concrete Forms (ICF’s) with a keyed footer.
A basement foundation is nothing more than a deeper crawl space, mostly underground, that is either finished or unfinished. The main item for basements is to make sure you get the exterior waterproofing and drainage setup properly to help control the water. As we mentioned above, a basement is constructed like a crawlspace, except for the slab & the height. If you are building a new house, it would definitely be worth looking into ICF’s & adding Insulation under the slab.
Choosing the proper type for you:
Choosing the proper foundation for your new home is gauged generally by five main items;
- The cost / your budget
- Your needs and / or desires
- What is popular in your area
- The Soil and / or Water Table
- Your climate
Well, as we stated above, there are three main types of foundations and we opted for choice 4. What is choice 4? It is a Post & Beam system, (also known as Pier & Beam or as a Raised Floor System) which is generally seen on coastal houses. Instead of utilizing a wall, we poured an adequate number of footings using the Bigfoot System around the perimeter of the building. On top of these footings, we installed 8×8 posts and anchors notched out to accept our LVL beams. We will be cover this all in more detail in our next article on the floor framing.
The good points:
- The ability to move the house later if required with minimal cleanup or demolition being required
- It is one of the greenest options available
- Less concrete & insulation is required
- No waterproofing, bricks, mortar, etc… is required
- It eliminates many health issues common with the other systems
- Moisture issues (mold, mildew, and rot) & flooding are eliminated with this system
- No chances for Radon to build up in an enclosed space
Yes folks, where there is good, there will be a little bad to go with it. In this case, it is courtesy of the Insurance companies. Due to it not being a “standard” system and generally only used on the coast, most carriers will not touch a house built like this. Even though this house was designed to handle winds up to 140 mph, one doesn’t have to worry about a water line breaking under a slab, or the basement or crawl flooding and damaging equipment, duct work, etc… they will not cover it as a regular house. Yes, it can be covered, but the premium was about 60% more than a standard policy.
With the exact same situation, I would definitely utilize this system. If the house moving was not an issue & slab on grade was not an option, I would still strongly consider this system instead of a crawl space or basement. I think the costs, and the benefits, far outweigh the penalty charged by the insurance companies. In all honesty, I hope the insurance companies all look at the issues involved & they just might se